Telematics units within mobile vehicles provide subscribers with connectivity to a telematics service provider (TSP). The TSP provides the subscriber with an array of services ranging from emergency call handling and stolen vehicle recovery to diagnostics monitoring and turn-by-turn navigation. Telematics units are often provisioned and activated at a point of sale when a subscriber purchases a telematics-equipped vehicle. Upon activation, the telematics unit can be utilized to provide a subscriber with the telematics services.
When the ignition of the mobile vehicle is off, vehicle hardware, such as the telematics unit, may be placed into a standby state or DRx (Discontinuous Receive) mode to minimize power drain on the vehicle battery. Often, a subscriber still wishes to use a variety of services provided by the vehicle even when the ignition is off (e.g. hands-free calling, GPS navigation, emergency calling, theft reporting, etc.), which may cause an excessive drain on the vehicle battery. This may lead to the battery running out of power and the vehicle ignition being subsequently unable to start the engine.
Further excessive drain can be cause by abnormal hung-up call states due to the complexity of processing multiple call types and multiple call durations. These hung-up states may be missing state in the network or in the network access device in the telematics unit. With the increase in wireless technologies that are added into the network access device in the telematics unit such as CDMA2000 1XRTT/EVDO, GSM/GPRS/EDGE, WCDMA/HSPA and LTE, the probability of missing call control can occur.
Thus, it is an object in part to provide a system and method for limiting excessive drain on the vehicle battery while maintaining as much functionality to the subscriber as possible when the vehicle ignition is off. However, while this is an object underlying certain implementations of the invention, it will be appreciated that the invention is not limited to systems that solve the problems noted herein. Moreover, the inventors have created the above body of information for the convenience of the reader and expressly disclaim all of the foregoing as prior art; the foregoing is a discussion of problems discovered and/or appreciated by the inventors, and is not an attempt to review or catalog the prior art.